WIP: Adding tests and yardoc to the #593 fix

Not for mergin quite yet.

jeffmccune has been helping me wrap my head around rspec, with a focus on building tests around the parsedfile provider.

The goal is to supply meaningful tests for both the commits that comprise the fix for #593 near the branch point.

Here's what happened so far: https://github.com/ffrank/puppet-scratch/pull/1